 | Bob Crager of Lewis Street Glass is a 26 year veteran in the glass business. Lewis Street Glass is a leading Wichita Glass company, serving the entire Wichita/Sedgwick County area since 1919. They do anything and everything having to do with glass, both residential and commercial. They also do Auto glass. They are located at 743 South Market, facing Kellogg on the South, and you can reach them by phone at (316) 263-8259. You can email Bob Crager at bcrager@lewisstreetglass.com |
Glass
2011-05-01 15:19:00
Keeping sunlight tolerable and the heat controlled
Answer: Window and door glass, commercial or residential, comes in all sizes, shapes, tints, can have multiple panes, many other configurations, and are all important to levels of satisfaction of the occupants of the buildings, as well as some security considerations. Reducing the energy costs associated with windows while increasing the human comforts, without excessive price increases, is a real challenge to the designers of new office buildings. Achieving an acceptable design depends upon many factors, all of which can contribute to the comfort levels, or lack thereof, experienced by the building’s occupants.
Such as:
•Which way the window faces
relative to the prevailing directions
of the mid-day sun.
•How much outside shading
is planned or is present for the
building’s windows.
•How bright the exterior scene
is to the eye, causing sometimes
unbearable glare.
•How dark the interior is (the
brighter the interior surfaces, the
less the window glare).
•The building owner or occupant’s
willingness to operate shading
devices to achieve their best
performance in controlling light
and heat.
•The building owner’s desire for
impact resistance, whether from
storm-blown objects or vandals.
•How critical it is to maintain an
unobstructed view to the outside
(gorgeous vistas shouldn’t be
permanently blocked by window
shades or other add-ons, although
temporary blocking for privacy or
solar heat rejection may be desired
at times.
•The building owner’s desire
for acoustic isolation in noisy
environments.
•Whether the window can meet
aesthetic desires for appearance
and quality.
There are some basic principles to keep in mind when selecting windows for buildings located in the Midwest areas of the country. The winter space-heating season is from short and mild, to long, severe, cold and brutal. The summertime cooling season can start in April, and run all the way through mid October in some years. Thus, there is a strong need to insulate a window, as well as to protect it from direct solar radiant heat gain. It is true that insulating the window with multiple panes, insulating gases and a special coating can reduce the size of the air conditioner needed to meet peak loads and that this smaller size will reduce both heating and cooling costs as well. Reduced heating and cooling equipment size could save enough construction dollars to pay for the extra cost of the window insulation, but this should be proven through calculations before being taken as the truth.
For retrofit applications, such as replacing windows in an existing building, there is seldom the chance to save dollars on the air conditioner, unless it just happens that the building owner needs to replace the air conditioner at the same time that the windows are replaced. If the owner decides to install insulated windows, for whatever reasons that make sense, a few extra comfort benefits can be expected too. For example, there will be less transfer of sound through the window, an advantage in urban settings with frequent road or aircraft noise, but a possible disadvantage for rural sites where the occupant might enjoy hearing the sound of the wind or the chirping of birds. Insulated windows have less of a tendency toward condensation, and/or the growth of mold and mildew. On the cold winter nights and excessively hot summer afternoons, an insulated window will be far and away more comfortable to sit near. In trying to prevent unwanted solar radiant heat gain during summer months in Kansas, it is best to minimize window exposures toward the east, southeast, south, southwest and west. This can be accomplished by the design and orientation of the building and by utilizing some shading techniques for the windows. During hot summers, it is far better, for heat gain prevention, to block the sunlight before it reaches the window, thereby dissipating the absorbed heat outside, where it can be carried away by the wind and air currents. This means that simple shade trees and other exterior shading methods can be very effective, both in saving air cooling energy, and in blocking the strong glare, which direct sunlight can produce if allowed inside. In the winter time, in the Midwest, the trees lose their leaves, allowing the sunshine and radiant heat through the trees and into your windows, thus helping to heat the interior of the building. If the owner and building designer cannot avoid windows facing the wrong directions, then the use of exterior operable shading devices could be considered to protect the windows from the sun in the summer. In many cases, darkening shades can be pulled down to reduce solar radiant heat gain along with its glare and higher energy costs. They can be opened when the sun is not shining directly on the window, or on overcast winter days, to provide both good exterior views and interior daylight illumination to the extent possible. A variety of exterior or interior shading devices are available. Proper planning can save big bucks in energy usage for just about any commercial or residential window application. Some information was researched on the worldwide web…More Next Month…
